Usage Patterns of Short-Acting β2-Agonists and Inhaled Corticosteroids in Asthma: A Targeted Literature Review.

Despite the availability of effective asthma treatments, some patients are poorly controlled because of overreliance on short-acting β2-agonists (SABAs) and underuse of inhaled corticosteroids (ICSs). To identify patient characteristics and outcomes associated with SABA overreliance and ICS underuse, we conducted a targeted literature review of the quantitative evidence on asthma medication use. Articles evaluating SABA and/or ICS use in patients with asthma (aged ≥12 years), published between January 2012 and March 2018, were identified using MEDLINE and EMBASE. We observed that studies classified SABA usage as "overuse," "high use," "excess use," "extreme overuse," "suboptimal use," and "inappropriate use." Multiple thresholds were used to define overuse of SABA (≥3 to ≥12 canisters/y). SABA overreliance was prevalent, with approximately 20% of adults using 3 or more canisters per year (≥12 inhalations/wk). Similarly, inappropriate ICS use, classified as "suboptimal," "high use," "underuse," and "unlicensed use," was defined by varying thresholds. Specific patient populations, such as older adults, smokers, and patients with low income, were more susceptible to SABA overreliance and ICS underuse. Overreliance on SABAs was associated with increased risk of severe exacerbations, asthma-related hospitalizations, emergency department visits, and asthma-related costs. These findings emphasize the prevalence and related burden of SABA overreliance at the potential expense of appropriate ICS use.